基于光纤的高精度时频传输技术研究

Highly precise aerospace measuring and controlling in the future will be confronted with the major challenge of accurately transferring synchronized time and standard frequency. Research of high precision time and frequency transferring technology based on optical fiber has important theory meaning and applied value. This project is established in the forefront of disciplines and the needs of national strategic development, and will focus efforts on:1) Integration of timing and keeping time: Solving the existing problem that the precision of timing is far worse than the precision of keeping time, by integrating time transfer and frequency transfer, studying multiplexing method and modulation technology to simultaneously transfer time and frequency, searching methods to realize high precision time and frequency transferring and controlling.2) Long dynamic range and high precision compensating methods: researching compensation system with long dynamic range to realize ultra-long distance, in the meantime, precise transferring of time and frequency and to solve the contradiction between range and precision of compensation. Through the above mentioned innovative research work, to achieve important breakthrough in the transmission module of long distance, high precision time and frequency microwave photonics signal in fiber, the multiplexing of simultaneously transferring time and frequency and feedback controlling. At last the new theories and technologies will be tested in the frist optical fiber based CEI system of our country at Beijing Aerospace Control Center and high precision, real time measuring and controlling of in-orbit spacecraft.These will provid a solid basis on the construction and development of high precision aerospace measuring and controlling system in the futrue.

在未来高精度航天测控中，面临着时间高精度同步和基准频率高精度传递的重大挑战。研究基于光纤的高精度时间、频率传递理论与技术，具有重要的科学价值和应用前景。本项目立足学科领域前沿和国家战略发展需要，重点研究：1）授时精度和守时精度统一协调机制：解决目前授时精度远远低于守时精度的矛盾，把时间传输和频率传输统一协调，探索实现高稳定度时频传输的机制及控制机制。2）大动态范围、高精度补偿机制：探索实现大动态补偿范围的机制，在实现超大距离传输的同时，实现高精度的时间、频率传递，解决补偿范围与补偿精度的矛盾。通过以上创新性研究工作，拟在长距离、高稳定度时频微波光子信号在光纤中传输模型、时频同时传输复用机制与反馈控制机制等方面实现重要突破，并在北京航天飞行控制中心国内首套基于光纤的CEI平台上进行测试验证实验,实现对在轨航天器的高精度实时测控，为推动高精度航天测控系统的建设与发展奠定坚实基础。

本项目立足学科领域前沿和国家战略发展需要，重点研究了基于光纤的大范围超高精度时间、频率传输的核心机理、技术途径与实现方法。应用于航天测控的高精度时频传输系统需要解决下面三个问题：1）基于光纤的长距离稳相传输；2）参考频率、时间信息、以及宽带射频信号同时传递；3）由中心站向多个基站进行时频信息的分布。. 针对地，项目1）提出了一种基于可调色散延时的链路时延抖动补偿方法，可以获得大范围（和光纤传输距离成正比的动态补偿范围）、高精度的补偿能力；2）基于上述稳相传输技术，进而提出了一种宽带、多载波同时稳相传输的方法，可以通过单个参考频率将整个光纤链路的延时稳定下来，从而保证同时传输的其它信息（包括本振、时间信号、及其其它任意射频信号）的稳相传输，并使得这些信息共享参考频率的高稳相精度；3）基于上述宽带同时稳相传输的技术，提出了一种环网结果时频信息分发技术，可以避免传统而复杂的点对点分配技术。. 项目既在实验室环境内实现了关键技术和指标验证，同时也搭建了集成、小型化、软硬件结合的原理样机。该样机在航天城飞行控制中心的相关平台上进行了长时间验证。基于以上成果，在项目执行期间累计发表8篇SCI收录的期刊论文，累计发表5篇国际会议论文，申请国家发明专利3项。